ScienceShot

ScienceShot: Fleeing Fruit Flies Perform Fancy Flying

If you’ve ever taken a swipe at a buzzing fly, you know how frustratingly fast the winged menaces can zip out of swatting range. Now, scientists have discovered the aerial maneuvers the common fruit fly (Drosophila hydei) utilizes in its speedy escape plan. The researchers placed about 50 fruit flies in a cylindrical drum containing three high-speed video cameras recording at 7500 frames per second (more than 300 times faster than the frame rate of a typical Hollywood blockbuster). When a fly flittered into the intersection of two laser beams at the center of the cylinder, it triggered an expanding shadow to form nearby, causing the fly to reflexively take evasive action. The researchers used video of the fleeing flies to construct a working 3D computer model of their body orientation and wing flaps. Whereas during normal flight flies lazily turn by adjusting their headings, spooked fruit flies turn five times faster by rolling their bodies sideways to perform rapid banked turns, the researchers report online today in Science. By rotating sideways using three to four precise wing flaps, the flies direct the forceful push generated by their wings to optimally boost the speed of their hairpin U-turn, as seen in the time-lapse photo above. The researchers say their findings suggest fruit flies have specialized sensory-motor circuits connecting their nervous systems and muscles that help them perform these quick movements and avoid swinging fly swatters.